🎗List the anatomic layers from anterior to posterior (6 items).
- Skin
- Subcutaneous (premammary) layer
- Mammary layer
- Retromammary space
- Muscle layer
- Chest wall
🎗List the anatomic layers from posterior to anterior (6 items).
- Chest wall
- Muscle layer
- Retromammary space
- Mammary layer
- Subcutaneous (premammary) layer
- Skin
The skin is composed of the ___ and ___ layers.
Epidermis and dermis
🎗The thickness of mammary skin is…
0.5 to 2 mm
T/F? The mammary skin is thinner in young females and thickens with age.
False, the opposite
The nipple consists of ___ tissue and ___ muscle.
dense connective tissue and erectile muscle
How many lactiferous duct openings may be seen on the nipple surface?
15-20
The circular area of dark pigmentation around the nipple is the…
areola
The areola consists of ___ muscle.
smooth
T/F? Areola skin is slightly thicker than surrounding skin.
True
🎗The small bumps on the areola are the…
Montgomery glands (a type of sebaceous gland)
This layer lies just beneath the skin extending to the mammary layer.
subcutaneous (premammary) layer
🎗The subcutaneous layer consists mostly of…
fat.
Which layer is NOT seen posterior to the nipple?
subcutaneous
T/F? The amount of fat in the subcutaneous layer increases with age, pregnancy, and obesity.
True
What appears as prominent structures within the subcutaneous layer?
Cooper’s ligaments
At the breast, this divides into superficial and deep layers.
superficial fascia
🎗Breast tissue is completely contained between…
2 layers of superficial fascia.
The superficial fascia is contained within the ___ layer anterior to the mammary layer.
subcutaneous
The mammary layer is also known as the…
Parenchymal or Glandular layer
🎗What is the Axillary Tail of Spence?
the portion of glandular tissue that extends into the axilla
The mammary layer is composed of ___ and ___ tissue.
Stromal and Epithelial tissue
Which is the supportive tissue of the breast?
stromal
Which type of tissue consists of interlobular fat, Cooper’s ligaments, and loose and dense connective tissue?
stromal
Which is the functional tissue of the breast?
epithelial
Which type of tissue consists of acini, lobules, TDLU’s, lobes, and lactiferous ducts?
epithelial
🎗These are ‘suspensory’ - part of the stroma and supportive tissue of the mammary layer.
Cooper’s ligaments
🎗These provide the architectural ‘framework’ of the breast.
Cooper’s ligaments
Where can Cooper’s ligaments be found?
running between the superficial and deep layers of the superficial fascia
🎗This is also called Acinus or Acinar cell.
Acini
What is the smallest functional unit of the breast?
Acini
🎗What is the milk-producing gland?
Acini
T/F? There are tens of acini in each breast.
False, hundreds
🎗Each acini gives rise to a ___ or ___.
ductule or terminal duct
This is composed of approximately 30 acini, intralobular terminal ducts, and loose (stromal) connective tissue.
Lobule
What is a lobule composed of?
approximately 30 acini, intralobular terminal ducts, and loose (stromal) connective tissue
What does TDLU stand for?
Terminal Duct Locular Unit
🎗TDLU is made up of…
lobule, intralobular terminal ducts, and an extralobular terminal duct
How big is a TDLU?
2 mm or less
🎗Where does nearly all breast pathology originate?
TDLU
Several lobules make up a…
breast lobe
🎗How many lobes in each breast?
15-20
How many lactiferous ducts emerge from each lobe and travel toward the nipple?
One
What transports milk from the acini to the nipple?
lactiferous ducts
Where is an intralobular terminal duct?
within the lobule
Where is an extralobular terminal duct?
outside the lobule
Where is an interlobular duct?
between the lobules
🎗What does a lactiferous duct do beneath the areola?
enlarge to form the lactiferous sinus
What kind of duct empties milk from the nipple?
collecting duct
Lactiferous ducts are lined with ___ and ___ cells
epithelium and myoepithelium
T/F? the myoepithelium is the inner lining of the lactiferous ducts.
False, the epithelium is the inner lining
The epithelium cells of the lactiferous ducts are supported by the…
basement membrane (adventitia)
Which is the outer fibrous portion of the lactiferous duct?
basement membrane (adventitia)
🎗What is the function of the myoepithelium in the lactiferous ducts?
to propel the milk toward the nipple (myo = muscle)
Where is the deep fascia located?
within the retromammary space posterior to the mammary layer
Why is maintaining the integrity of the deep fascia important?
to deter the spread of cancer to the chest wall
The retromammary space is between the ___ and the ___.
posterior margin of the mammary layer and the pectoral muscles
The retromammary space contains a thin layer of…
fat.
T/F? the amount of fat in the retromammary space increases with age, pregnancy, and obesity.
True
The retromammary space contains the [superficial/deep] layer of superficial fascia.
deep
What allows for movement of the breast over the chest wall?
the retromammary space
Which muscle arises from the clavicle and costal cartilage of the sternum?
pectoralis major
Which muscle attaches to the proximal humerus?
pectoralis major
Which muscle arises from the 3rd, 4th, and 5th ribs?
pectoralis minor
Which muscle attaches to the scapula?
pectoralis minor
This encloses the chest muscles and may appear deep to the retromammary layer.
the pectoral (muscular) fascia
Which is more anterior - pectoralis major or minor?
major
Ribs are located [anterior/posterior] to the pectoral muscles.
posterior
🎗In small-breasted females, don’t confuse a rib with a ___.
intramammary tumor
Intercostal muscles are located…
between the ribs.
The lung is ___ to the chest wall layer.
deep
Glandular tissue is usually thicker in which quadrant of the breast?
Upper Outer
🎗In which quadrant of the breast is the largest percentage of cancers found?
Upper Outer
What is important to correlate when using Clock Method anatomic reference.
Rt vs Lt
Breast enlargement in newborns may be seen due to…
placental and maternal hormone stimulation.
The early mammary gland begins development during the ___ week of embryonic life.
4th
At ___ weeks gestation testosterone in the male fetus prohibits further development.
15
The ‘milk line’ extends from the ___ to the ___.
axilla to the inguinal region
amastia
absence of one or both breasts
polymastia
accessory breast or more than two breasts
🎗athelia
absence of the nipple
🎗polythelia
accessory nipple (most common anomaly)
🎗amazia
absense of the breast tissue with development of the nipple
unilateral early ripening
asymmetric growth of the breasts
T/F? Polythelia is more common in women than men.
False, men than women
Which two main arteries supply blood to the breast tissues?
lateral thoracic artery and internal mammary artery
T/F? The lateral thoracic artery arises from the axillary artery.
True
T/F? The internal mammary artery arises from the axillary artery.
False, the subclavian
Which artery is often used in coronary artery bypass grafts?
The internal mammary artery
Two secondary sources of blood supply to the breast tissues are…
the thoracoacromial artery (superior region) and the intercostal artery (inferior margin)
🎗 The superficial veins of the breast are located just ___ to the superficial fascia.
deep
What is the communication route that allows cancer to metastasize to the opposite breast?
the superficial veins
What are the deep veins of the breast? (5)
- internal mammary vein
- lateral thoracic vein
- axillary vein
- subclavian vein
- intercostal vein
What is the communication route that allows cancer to metastasize to the bone?
the intercoastal veins with the vertebral veins
Which system closely follows the superficial and venous system of the breast?
the lymphatic vessels of the breast
🎗Breast cancer most frequently spreads by ___.
hematogeneous route
Where does lymph flow begin?
From the stroma and lactiferous ducts (deep system)
🎗 Lymph flow direction is [away from/towards] the areola and periareolar plexus on the way to the superficial system.
Towards
Name the 6 groups of nodes in the Axillary Lymph Node Chain.
- External Mammary
- Scapular
- Axillary
- Central
- Subclavicular
- Interpectoral (Rotter’s nodes)
Where are the External Mammary lymph nodes?
along the lateral thoracic vessels
Where are the Scapular lymph nodes?
with the subscapular vessels
Where are the Axillary lymph nodes?
with the axillary vessels
Where are the Central lymph nodes?
with the axillary vessels
Where are the Subclavicular lymph nodes?
with the subclavicular vessels
Where are the Interpectoral (Rotter’s) lymph nodes?
between pectoralis major and minor muscles
🎗Approx how much of the lymphatic drainage is to the axilla?
75%
Besides the Axillary Lymph Node Chain, where does the remaining drainage go? [5]
- Internal Mammary (w/ the internal mammary vessels)
- Intercostal
- Flow to the opposite breast
- Supraclavicular
- Diaphrgmatic - allows draining to the abd (thus liver mets)
🎗 Lymph nodes have what sort of shape?
reniform (kidney-like)
Define afferent
moving toward
Define efferent
moving away
What vessels carry lymph into the lymph node through the cortex where it is filtered?
Outer Afferent Lymphatic Vessels
What vessel carries lymph back into the system from the lymph node hilum?
Efferent Lymphatic Vessel
Name 7 mammary nerves
- long thoracic nerve
- thoraco-dorsal nerve
- thoracic intercostal nerves
- 3rd and 4th branch of the cervical plexus
- 🎗 circumflex nerve
- subscapular nerves
- anterior thoracic nerves
What is thelarche?
At puberty, breast development occurring due to the hormonal stimulation by the ovaries.
🎗Estrogen stimulates changes of the ___ tissues.
stromal - elongation of the mammary ducts, connective tissue growth, increase in adipose, increased vascularity
🎗 Progesterone stimulates changes of the ___ tissues.
glandular - TDLUs
🎗 Late in pregnancy, the ___ increase in size in preparation for lactation.
lactiferous ducts
🎗 What do the hormones do shortly after birth?
estrogen and progesterone drop and prolactin dominates
How long after ceasing lactation does it take for ducts and lobules to return to normal size?
approx 3 months
What are the most common causes of glandular tissue increase with age? (3)
- pregnancy/lactation
- hormone replacement therapy (HRT)
- significant weight loss
🎗 The ratio of glandular to fatty tissue is determined by…
…the patient’s BMI.
Total Body Fat: Total Body Weight
